const connection = require('../app/database')
class MomentService {
  async create (userId, content) {
    const statement = `INSERT INTO moment (content, user_id) VALUES (?, ?)`
    const [result] = await connection.execute(statement, [content, userId])
    return result
  }
  async getMomentById (id) {
    const statement = 
      `SELECT
          m.id id, m.content content, m.createAt createTime, m.updateAt updateTime,
          JSON_OBJECT('id', u.id, 'name', u.name, 'avatarUrl', u.avatar_url) author,
          IF(COUNT(l.id), JSON_ARRAYAGG(
            JSON_OBJECT('id', l.id, 'name', l.name)
          ), NULL) labels,
          (SELECT IF(COUNT(c.id), JSON_ARRAYAGG(
            JSON_OBJECT('id', c.id, 'content', c.content, 'commentId', c.comment_id, 'createTime', c.createAt, 'user', JSON_OBJECT('id', cu.id, 'name', cu.name, 'avatarUrl', cu.avatar_url))
          ), NULL)
        FROM comment c LEFT JOIN user cu ON c.user_id = cu.id WHERE m.id = c.moment_id) comments,
        (SELECT JSON_ARRAYAGG(CONCAT('http://localhost:8000/moment/images/', file.filename))
        FROM file WHERE m.id = file.moment_id) images
        FROM moment m
        LEFT JOIN user u ON m.user_id = u.id
        LEFT JOIN moment_label ml ON m.id = ml.moment_id
        LEFT JOIN label l ON ml.label_id = l.id
        WHERE m.id = ?
        GROUP BY m.id
        `
    const [result] = await connection.execute(statement, [id])
    return result[0]
  }
  async getMomentList(offset, size) {
    const statement =
    `SELECT
        m.id id, m.content content, m.createAt createTime, m.updateAt updateTime,
        JSON_OBJECT('id', u.id, 'name', u.name) author,
        (SELECT COUNT(*) FROM comment c WHERE c.moment_id = m.id) commentCount,
        (SELECT COUNT(*) FROM moment_label ml WHERE ml.moment_id = m.id) labelCount,
        (SELECT JSON_ARRAYAGG(CONCAT('http://localhost:8000/moment/images/', file.filename))
        FROM file WHERE m.id = file.moment_id) images
      FROM moment m
      LEFT JOIN user u ON m.user_id = u.id 
      LIMIT ?, ?
    `
    const [result] = await connection.execute(statement, [offset, size]);
    return result;
  }
  async update (content, momentId) {
    const statement = `UPDATE moment SET content = ? WHERE id = ?`
    const [result] = await connection.execute(statement, [content, momentId])
    return result
  }
  async remove (momentId) {
    const statement = `DELETE FROM moment WHERE id = ?`
    const [result] = await connection.execute(statement, [momentId])
    return result
  }
  async hasLabel (momentId, labelId) {
    const statement = `SELECT * FROM moment_label WHERE moment_id = ? AND label_id = ?`
    const [result] = await connection.execute(statement, [momentId, labelId])
    return result[0] ? true : false
  }
  async addLabel(momentId, labelId) {
    const statement = `INSERT INTO moment_label (moment_id, label_id) VALUES (?, ?);`
    const [result] = await connection.execute(statement, [momentId, labelId])
    return result
  }
}
module.exports = new MomentService()